The present invention relates to a method and a system for processing fish, in particular sardines.
In the foodstuffs industry there is a need for automated processes for separating the non-consumable end waste parts of the fish from the consumable body part of the fish. The end waste parts may constitute the head, gills and tail of the fish. The present invention seeks to provide a system and a method for the above task.
Previous technologies, such as e.g. U.S. Pat. No. 4,551,885, typically provide a conveyer belt where the fish is placed in a specific position. Such specific position is typically determined by arranging the fish into a standardized compartment substantially corresponding to the anatomy of a standard fish or simply by arranging the fish against a fixed object, such as the wall or side of the conveyer belt. The conveyer belt transports the fish towards a fixed knife arrangement placed in a position suitable for decapitating a standard fish for which the arrangement was designed. The knife arrangement divides the fish into a head and gills part and a body part, where the tail belongs to the body part.
The drawback of the arrangement described above is evident, since it presumes that all fish to be processed are having exactly the same anatomy. However, even within a species of fish the size and in particular the position of the gills will differ significantly. To ensure no part of the head or gills remains with the body of the fish after decapitation, a substantial safety margin must be used when determining the position of the knife to allow for anatomic variations of the fish. The margin constitutes a loss since the meat remaining with the head and gills part of the fish after decapitation cannot be further processed and must be disposed or sold at a considerable lower price than the price of the meat in the body part of the fish. It has been estimated that in average approximately 10% of valuable fish meat remains with the head and gills part of the fish, since according to the fish anatomy the thickest part of the fish body and thereby the most meat is located near the gills. Consequently, even using a relatively small margin a relatively large amount of meat will be lost for further processing.
It would therefore be beneficial to have a process where each specific fish is cut in an optimal position in respect to the position of the gills of each specific fish. It is, however, very difficult to identify the position of the gills by an automatic process due to the smooth surface of the fish.